Just to contribute to the complicated algebra:
With your struct file the volume (:VOL in scf) is:
:VOL : UNIT CELL VOLUME = 1072.33603
This is different from what you wrote in your email ??? !!!!
> coming as 1073.2425 bohr^3 which get doubles when we consider ....
If I do
x optimize
option 3 (not 2, which is for tetragonal and hexagonal lattices!!!!)
and 0 and 2% change:
ca-test_coa____0.00.struct
11.264663 11.699300 16.273574 90.000000
ca-test_coa____2.00.struct
11.190551 11.622329 16.489838 90.000000
--------------------------------------------------
cp ca-test_coa____2.00.struct ca-test.struct
x lapw0
grep :VOL *scf0
The volume is still the same.
Am 12.06.2020 um 17:32 schrieb shamik chakrabarti:
Another thing is that from volume optimization the unit cell volume is
coming as 1073.2425 bohr^3 which get doubles when we consider the volume
of a conventional cell to become 2146.485 bohr^3 while the printed
volume of a conventional unit cell after c/a optimization is coming as
2058.7690 bohr^3 ; Why is this discrepancy? Is it that the conventional
cell volume about 1.9183 times the unit cell volume & not as I have
assumed. I am sending the fully optimized struct (according to my
calculation) file for your consideration.
with regards,
On Fri, 12 Jun 2020 at 20:46, shamik chakrabarti
<[email protected] <mailto:[email protected]>> wrote:
Dear Tomas,
Can you please elaborate how to know a', b' and c'
(the final lattice parameters) from a unit cell volume optimization
with a:b:c = constant (where a, b, c are initial lattice parameters) ?
with regards,
On Fri, 12 Jun 2020 at 17:15, Tomas Kana <[email protected]
<mailto:[email protected]>> wrote:
Dear Shamik,
Ok, I undestand your point.
But anyway, I think, that the problem comes
from your equation.
If you want to relax c/a with constant volume and
constant b/a then I would prefer these eqations:
original c/a = cAoriginal
b/a = bAconstant
new c/a = cAnew
original volume a*b*c
new volume (the same as original)
aNew * bNew * cNew =
aNew * (aNew * bAConstant) * (aNew * cAnew) =
aNew^3 * bAConsant*cAnew = original volume
You choose your desired cAnew and know0 bAconstant
and the original volume.
In this way, you obtain the aNew and it is easy to
obtain bNew and cNew then. But I still do not understand the
parameter x in your eqation.
Maybe this could be the source of your error?
Hope this helps
Tomas
Dear Tomas,
I am sorry to say that you have misunderstood
my equation. I have used abcx^3 = a'b'c' where a', b' and c' are
the new lattice parameters & not the old a,b,c !!! :)
with regards,
On Fri, 12 Jun 2020 at 16:31, Tomas Kana <[email protected]
<mailto:[email protected]>> wrote:
Dear Shamik,
If you want to keep a constant volume and
you use the equation
abcx^3 = 332.934 = abc then only one solution is possible:
x = 1. ax = a, bx = b cx = c.
Your equation does not make sense to me....
With best regards
Tomas Kana
where a, b, c are the initial lattice parameters. From that
equation I have found the value of x & then finally multiply x
with each lattice parameters to get new lattice parameters as
a* = ax, b*=bx & c*=cx & then put
---------- Původní e-mail ----------
Od: shamik chakrabarti <[email protected]
<mailto:[email protected]>>
Komu: A Mailing list for WIEN2k users
<[email protected]
<mailto:[email protected]>>
Datum: 12. 6. 2020 10:05:37
Předmět: Re: [Wien] Volume has changed during running
optimization of c/a
with constant volume & b/a
No, I have created a new directory for c/a optimization. I have
done the followings,
abcx^3 = 332.934 where a, b, c are the initial lattice
parameters. From that equation I have found the value of x &
then finally multiply x with each lattice parameters to get new
lattice parameters as a* = ax, b*=bx & c*=cx & then put
a*,
b* & c* as new inputs for c/a optimization with constant volume
in a new directory.
with regards,
On Fri, 12 Jun 2020 at 13:23, Peter Blaha
<[email protected]
<mailto:[email protected]>> wrote:
How did you do:
"putting the lattice parameters as input for c/a optimization" ???
If you continue in the previous directory, do you realize that
there is
a case_initial.struct which, if present, is taken a "base
struct file".
Am 12.06.2020 um 04:12 schrieb shamik chakrabarti:
> Dear wien2k users,
>
> I am running wien2k 19.1. I have started c/a
optimization
> with constant volume and b/a for an ABO4 compound. From volume
> optimization with a:b:c=constant I have obtained an unit cell
volume of
> 332.934 Ang^3. While after calculation of lattice parameters
and putting
> the lattice parameters as input for c/a optimization with
*constant
> volume* & b/a, the printed unit cell volume is coming
as 312.8004 Ang^3.
>
> Where I am doing wrong?
>
> Thanks in advance.
>
> with regards,
> --
> Dr. Shamik Chakrabarti
> Research Fellow
> Department of Physics
> Indian Institute of Technology Patna
> Bihta-801103
> Patna
> Bihar, India
>
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--
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TU Vienna
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Austria
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Dr. Shamik Chakrabarti
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Indian Institute of Technology Patna
Bihta-801103
Patna
Bihar, India
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Dr. Shamik Chakrabarti
Research Fellow
Department of Physics
Indian Institute of Technology Patna
Bihta-801103
Patna
Bihar, India
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Dr. Shamik Chakrabarti
Research Fellow
Department of Physics
Indian Institute of Technology Patna
Bihta-801103
Patna
Bihar, India
--
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Research Fellow
Department of Physics
Indian Institute of Technology Patna
Bihta-801103
Patna
Bihar, India
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